Difference between revisions of "GPS"
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=====GPS===== | =====GPS===== | ||
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The Global Positioning System (GPS) is a worldwide radio-navigation system formed from a constellation of 24 satellites and their | The Global Positioning System (GPS) is a worldwide radio-navigation system formed from a constellation of 24 satellites and their ground stations. | ||
GPS uses these "man-made stars" as reference points to calculate positions accurate to a matter of meters. In fact, with advanced forms of GPS you can make measurements to better than a centimetre! | GPS uses these "man-made stars" as reference points to calculate positions accurate to a matter of meters. In fact, with advanced forms of GPS you can make measurements to better than a centimetre! | ||
In a sense it's like giving every square meter on the planet a unique address. | In a sense it's like giving every square meter on the planet a unique address. | ||
GPS receivers have been miniaturized to just a few integrated circuits and so are becoming very economical. And that makes the technology accessible to virtually everyone. | GPS receivers have been miniaturized to just a few integrated circuits and so are becoming very economical. And that makes the technology accessible to virtually everyone. | ||
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=====How Does GPS Work?===== | |||
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[1] The basis of GPS is [["triangulation"]] from satellites. | |||
[2] To "triangulate," a GPS receiver measures distance using the travel time of radio signals. | |||
[3] To measure travel time, GPS needs very accurate timing which it achieves with some tricks. | |||
[4] Along with distance, you need to know exactly where the satellites are in space. High orbits and careful monitoring are the secret. | |||
[5] Finally you must correct for any delays the signal experiences as it travels through the atmosphere. | |||
Revision as of 15:46, 25 March 2006
GPS
The Global Positioning System (GPS) is a worldwide radio-navigation system formed from a constellation of 24 satellites and their ground stations.
GPS uses these "man-made stars" as reference points to calculate positions accurate to a matter of meters. In fact, with advanced forms of GPS you can make measurements to better than a centimetre!
In a sense it's like giving every square meter on the planet a unique address.
GPS receivers have been miniaturized to just a few integrated circuits and so are becoming very economical. And that makes the technology accessible to virtually everyone.
How Does GPS Work?
[1] The basis of GPS is "triangulation" from satellites.
[2] To "triangulate," a GPS receiver measures distance using the travel time of radio signals.
[3] To measure travel time, GPS needs very accurate timing which it achieves with some tricks.
[4] Along with distance, you need to know exactly where the satellites are in space. High orbits and careful monitoring are the secret.
[5] Finally you must correct for any delays the signal experiences as it travels through the atmosphere.